Bone enhancement device and method

ABSTRACT

There is provided in accordance with an exemplary embodiment of the invention a method of osteointegration of an implant into surrounding jaw-bone, the method comprising: applying a magnetic field around an implant, the magnetic field produced around the implant to a jaw-bone depth of up to at least about 7 mm, the magnetic field having a magnetic flux density of about 0.05-0.5 mT at up to at least about 2 mm from a surface of the implant, the magnetic field produced by a coil within the implant. A device adapted for insertion into a jawbone implant and for producing the magnetic field for bone enhancement of surrounding jawbone is also described.

RELATED APPLICATIONS

This application is a National Phase of PCT Patent Application No.PCT/IL2013/050370 having International filing date of May 2, 2013, whichclaims the benefit of priority under 35 USC §119(e) of U.S. ProvisionalPatent Application No. 61/641,995 filed May 3, 2012.

This application is also related to PCT WO 2011/051947, entitled“IMPLANT DEVICE FOR STIMULATING OSTEOGENESIS AND OSSEOINTEGRATION”,filed with the same common inventor Moshe NEUMAN. The contents of theabove applications are all incorporated by reference as if fully setforth herein in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to a medicalimplant device and, more particularly, but not exclusively, to a devicefor bone enhancement by application of electromagnetic fields.

U.S. Pat. No. 5,292,252 by Nickerson et al. disclose “A stimulatorhealing cap is disclosed for enhancing and speeding the growth of bonecells and bone tissue surrounding a dental implant.”

Matsumoto, H et al. “Pulsed Electromagnetic Fields Promote BoneFormation around Dental Implants Inserted into the Femur of Rabbits”,Clin Oral Impl Res 2000:11:354-360. discloses “These results suggestthat PEMF stimulation may be useful for promoting bone formation aroundrough-surfaced dental implants.”

Song J K et al. “An electronic device for accelerating bone formation intissues surrounding a dental implant” Bioelectromagnetics. 2009 July;30(5):374-84. disclose “Based on these results showing accelerated boneformation on and around the dental implant, it could be suggested thatthe latent time for osseointegration in dental implants can be reduced,and the success rate of implants in poor quality bone can be increased”.

Additional background art includes:

U.S. patent application 2006/0265026 by Madjar et al.

U.S. Pat. No. 6,605,089 by Michelson et al.

U.S. patent application 2004/0176805 by Whelan et al.

SUMMARY OF THE INVENTION

An aspect of some embodiments of the invention relates to an enhancementdevice adapted to produce a magnetic field to enhance osteointegrationof a jaw bone implant.

There is provided in accordance with an exemplary embodiment of theinvention a method of osteointegration of an implant into surroundingjaw-bone, the method comprising:

applying a magnetic field around an implant, the magnetic field producedaround the implant to a jaw-bone depth of up to at least about 7 mm, themagnetic field having a magnetic flux density of about 0.05-0.5 mT at upto at least about 2 mm from a surface of the implant, the magnetic fieldproduced by a coil within the implant.

In an exemplary embodiment of the invention, the magnetic flux densityis about 0.2-0.45 mT at up to at least about 1 mm from the surface.

In an exemplary embodiment of the invention, the magnetic flux densityis about 0.2-0.3 mT at up to at least about 2 mm from the surface.

In an exemplary embodiment of the invention, applying comprises applyingthe magnetic field around at least 80% of the depth.

In an exemplary embodiment of the invention, applying comprises applyingthe magnetic field lines in a primarily parallel direction within +/−15degrees to a long axis of the implant.

In an exemplary embodiment of the invention, applying comprises applyingthe magnetic field with a gradient perpendicular to the surface of theimplant.

In an exemplary embodiment of the invention, the magnetic field variesover time with a frequency ranging from 0.5 Hz to 50 Hz.

In an exemplary embodiment of the invention, applying comprises applyinga current pulse at a repetition rate of 0.5 Hz to 50 Hz.

In an exemplary embodiment of the invention, applying comprisesproducing a pulse duration of current that ranges from about 30 to 70microseconds followed by a wait time that is 1500-2400 times as long asthe pulse duration.

In an exemplary embodiment of the invention, applying comprises applyinga sinusoidal pulse of current to produce the magnetic field.

In an exemplary embodiment of the invention, applying comprises applyinga biphasic pulse of current to produce the magnetic field.

In an exemplary embodiment of the invention, applying comprises applyingthe magnetic field continuously for a period of 30 to 70 days.

In an exemplary embodiment of the invention, applying comprises applyinga current to produce the magnetic field having a peak amplitude from 50mA to 100 mA.

In an exemplary embodiment of the invention, the method furthercomprises deciding to enhance osteointegration of a dental implant intothe jawbone.

In an exemplary embodiment of the invention, the depth of the implantcomprises a portion of the implant only in contact with trabecular bone.

In an exemplary embodiment of the invention, applying a magnetic fieldaround an implant is controlled by remote activation using an externallyapplied field.

There is provided in accordance with an exemplary embodiment of theinvention a device adapted for insertion into a jawbone implant and forbone enhancement of surrounding jawbone, the device comprising:

a first transmitter arranged to transmit at least one of a magnetic andelectric field for the bone enhancement; and

a magnetic switch coupled to activate the first transmitter, themagnetic switch activated by an external magnetic field.

In an exemplary embodiment of the invention, the magnetic field isconfigured to promote osteointegration of the jaw bone implant in thejaw bone. Optionally, the jaw bone implant is a base for an artificialtooth.

In an exemplary embodiment of the invention, the first transmittercomprises a coil.

In an exemplary embodiment of the invention, at least a portion of thefirst transmitter is further arranged as a receiver, and the externalmagnetic field is received on the first transmitter. Optionally, thedevice further comprises an attenuator arranged to prevent selfactivation of the first transmitter.

In an exemplary embodiment of the invention, a system adapted for boneenhancement comprises:

an implantable device; and

a second transmitter arranged to transmit the external magnetic field.

Optionally, the second transmitter is arranged as a coil having acentral hole large enough for insertion of the implantable devicetherein. In an exemplary embodiment of the invention, the secondtransmitter is incorporated in a cradle shape and the implantable deviceis inserted into the central hole of the cradle. Optionally, the cradleis small enough to be placed inside the mouth.

In an exemplary embodiment of the invention, the cradle is arranged fortesting the power level generated by the implantable device by measuringa current induced by the magnetic field on the transmitter coil.

In an exemplary embodiment of the invention, the cradle comprises aninput for allowing remote activation of the implantable device by auser, and an output for allowing a user to determine a state of theimplantable device.

In an exemplary embodiment of the invention, the external magnetic fieldis coded for programming a controller controlling the first transmitter,the controller disposed in the implantable device. Optionally oradditionally, the external magnetic field is arranged for wirelesslycharging batteries in the implantable device.

There is provided in accordance with an exemplary embodiment of theinvention a device adapted for insertion into a jawbone implant and forbone enhancement of surrounding jawbone, the device comprising:

a wire coil wound and stacked around a core, the wire and the corearranged to produce a bone enhancing magnetic field in bone around thedevice, a number of turns of the wire, a diameter of the wire and anumber of stacks arranged to reduce heating and increase the magneticfield.

In an exemplary embodiment of the invention, the wire and core arearranged to reduce heating of the surrounding bone.

In an exemplary embodiment of the invention, the device is sized andarranged for insertion in a jaw bone implant for an artificial tooth toreach to the end of a cavity in the implant.

In an exemplary embodiment of the invention, a diameter of the wireranges from about 10 μm to about 80 μm.

In an exemplary embodiment of the invention, a diameter of the coil whenwound around the core is about 800 μm to about 1150 μm.

In an exemplary embodiment of the invention, a number of turns of thewire around the core ranges from about 450 to about 550.

In an exemplary embodiment of the invention, the bone is heated by about0.02 degrees Celsius to about 3 degrees Celsius during steady state.

In an exemplary embodiment of the invention, the heating of the bone andthe magnetic field are selected to synergistically increaseosteointegration in the bone.

In an exemplary embodiment of the invention, the device furthercomprises an outer screw sheath, the core contained within the outerscrew sheath and the core removable from the sheath. Optionally, thescrew sheath is adapted for direct engagement with bone. Optionally, thescrew sheath is coated with one or more drugs.

There is provided in accordance with an exemplary embodiment of theinvention an energy saving circuit configured for a bone enhancementdevice insertable in a jawbone implant, the circuit comprising:

a coil arranged to produce a bone enhancing magnetic field;

a capacitor in series with the coil, the capacitor being able to storesufficient charge to pass a current through the coil to produce themagnetic field;

one or more switches in series with the capacitor; and

a controller to:

-   -   control the switches to maintain the capacitor at a first        voltage value during a non-pulse phase, wherein no significant        magnetic field is produced,    -   control the switches to charge the capacitor to a second voltage        value, the second voltage value equal to about the first voltage        value, the second voltage value having a charge opposite to the        first voltage value; and    -   control the switches to charge the capacitor from the second        voltage value back to the first voltage value, the charging        occurring over a time period of a pulse phase, wherein the        charging the capacitor comprises passing a current through the        coil to produce the magnetic field, the current related to a        voltage drop across the coil of about two times the first        voltage.

In an exemplary embodiment of the invention, a ratio between themaintaining and the charging ranges from about 1:750 to about 1:5000.

In an exemplary embodiment of the invention, charging to the secondvoltage occurs within about 25 microseconds.

In an exemplary embodiment of the invention, charging back to the firstvoltage value occurs within about 25 microseconds.

In an exemplary embodiment of the invention, a voltage source of about 3Volt is used.

In an exemplary embodiment of the invention, the current to produce themagnetic field reaches a peak to peak of about 130 mA.

In an exemplary embodiment of the invention, a peak current is reachedduring one voltage swing.

In an exemplary embodiment of the invention, a wait period between afirst of the charging and a second of the charging is 750-5000 times thetime taken for the first charging.

In an exemplary embodiment of the invention, energy not used inproducing the magnetic field by the coil is collected in the capacitorand used for the next transmission.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiments of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

Implementation of the method and/or system of embodiments of theinvention can involve performing or completing selected tasks manually,automatically, or a combination thereof. Moreover, according to actualinstrumentation and equipment of embodiments of the method and/or systemof the invention, several selected tasks could be implemented byhardware, by software or by firmware or by a combination thereof usingan operating system.

For example, hardware for performing selected tasks according toembodiments of the invention could be implemented as a chip or acircuit. As software, selected tasks according to embodiments of theinvention could be implemented as a plurality of software instructionsbeing executed by a computer using any suitable operating system. In anexemplary embodiment of the invention, one or more tasks according toexemplary embodiments of method and/or system as described herein areperformed by a data processor, such as a computing platform forexecuting a plurality of instructions. Optionally, the data processorincludes a volatile memory for storing instructions and/or data and/or anon-volatile storage, for example, a magnetic hard-disk and/or removablemedia, for storing instructions and/or data. Optionally, a networkconnection is provided as well. A display and/or a user input devicesuch as a keyboard or mouse are optionally provided as well.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention are herein described, by way ofexample only, with reference to the accompanying drawings and/or images.With specific reference now to the drawings in detail, it is stressedthat the particulars shown are by way of example and for purposes ofillustrative discussion of embodiments of the invention. In this regard,the description taken with the drawings makes apparent to those skilledin the art how embodiments of the invention may be practiced.

In the drawings:

FIG. 1A is a schematic of an exemplary bone enhancement device, inaccordance with an exemplary embodiment of the invention;

FIG. 1B is a block diagram of a bone enhancement system, in accordancewith an exemplary embodiment of the invention;

FIG. 2 is a schematic showing implantation of the enhancement deviceinside a jawbone implant, in accordance with an exemplary embodiment ofthe invention;

FIG. 3 is a method of treatment using the enhancement device, inaccordance with an exemplary embodiment of the invention;

FIGS. 4A-4D are isometric views of various assembly levels of theenhancement device, in accordance with an exemplary embodiment of theinvention;

FIGS. 5A-5C are cross sectional views of the enhancement device, inaccordance with an exemplary embodiment of the invention;

FIG. 6 is a cross sectional view of the ferrite core and winding wire ofthe enhancement device, in accordance with an exemplary embodiment ofthe invention;

FIG. 7A is a graph illustrating an exemplary magnetic field produced bythe enhancement device, in accordance with an exemplary embodiment ofthe invention;

FIG. 7B is an image of an exemplary enhancement device to helpunderstand the field as in FIG. 7A;

FIG. 7C is the raw data used of FIG. 7A in table format;

FIG. 8A is a schematic of an energy saving circuit, in accordance withan exemplary embodiment of the invention;

FIGS. 8B-C are graphs to help understand the function of the circuit ofFIG. 8A;

FIG. 9 is a circuit diagram of circuitry to control the enhancementdevice, in accordance with an exemplary embodiment of the invention;

FIGS. 10A-10C are schematics of an activation cradle to control theenhancement device, in accordance with an exemplary embodiment of theinvention;

FIG. 11 is a circuit diagram of an energy saving mechanism, inaccordance with an exemplary embodiment of the invention;

FIGS. 12A-12B are CT scans to help understand an experiment, inaccordance with an exemplary embodiment of the invention;

FIGS. 13A-13B are graphs of the experimental results based on a twodimensional analysis;

FIG. 14 shows some exemplary CT scans to help understand theexperimental results;

FIG. 15 is a graphical representation of results based on a threedimensional analysis; and

FIG. 16A-D show some exemplary CT scans to help understand theexperimental results.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to a medicalimplant device and, more particularly, but not exclusively, to a devicefor bone enhancement by application of electromagnetic fields.

An aspect of some embodiments of the invention relates to a method forenhancing and/or stimulating osteointegration of an implant tosurrounding bone. In an exemplary embodiment of the invention, a dentalimplant is integrated into surrounding jaw bone (e.g., mandible,maxilla).

In an exemplary embodiment of the invention, the magnetic field isapplied with a set of parameters, for example, the magnetic flux densityis about 0.2-0.45 mT at up to about 1 mm from the surface implant,and/or the magnetic flux density is about 0.2-0.3 mT at up to about 2 mmfrom the surface.

In an exemplary embodiment of the invention, the magnetic field is at agradient when measured perpendicular to the surface of the implant(e.g., within the first about 2 mm) For example, about 30 uTesla/mm, orabout 50 uTesla/mm, or about 100 uTesla/mm, or about 150 uTesla/mm, orabout 200 uTesla/mm, or about 250 uTesla/mm, or other smaller,intermediate or larger gradients.

In an exemplary embodiment of the invention, the magnetic field is at agradient when measured parallel to the surface of the implant (e.g.,within the first about 2 mm). For example, about 0 uTesla/mm, or 10UTesla/mm, or about 25 uTesla/mm, or about 50 uTesla/mm, or about 75uTesla/mm, or about 100 uTesla/mm, or about 150 uTesla/mm, or otherintermediate or larger gradients. The gradient is either positive ornegative, as in some places the magnetic field values increase andsometimes decrease.

In an exemplary embodiment of the invention, the magnetic flux densityis located around at least, for example, about 90% of the length of theimplant, or at least about 80% of the length, or at least about 70% ofthe length, or at least about 60% of the length, or at least about 50%of the length, or other smaller, intermediate or larger percentages.Alternatively or additionally, the magnetic field density is located ata jaw-bone depth (e.g., from the surface) of, for example, up to atleast about 3 mm, or 4 mm, or 5 mm, or 7 mm, or 10 mm, or 13 mm, orother smaller, intermediate or larger depths.

In an exemplary embodiment of the invention, the method comprisesapplying an electromagnetic field to bone surrounding the implant.Optionally or additionally, the method comprises stimulatingosteogenesis (e.g., new bone formation). Optionally or additionally, themethod comprises enhancing bone turnover (e.g., the process of removingexisting bone and replacing with new bone). Optionally or additionally,the method comprises stimulating and/or enhancing the activity ofosteoclasts and/or osteoblasts. Optionally or additionally, the methodcomprises improving bone quality, for example, with patients with lowbone density and/or weak bones (e.g., when compared to healthypatients). Optionally or additionally, the method comprises reducing thetime required for integration of an implant into surrounding bones.Optionally or additionally, the method comprises improvingosteointegration.

Some additional exemplary parameters are described in the section“Exemplary Magnetic Field Parameters”. In an exemplary embodiment of theinvention, the magnetic field is pulsed. The parameters causing the boneenhancement have been discovered by the inventors in an experiment.

In an exemplary embodiment of the invention, an electrical current ispassed through a coil to produce the electromagnetic field. Optionally,the coil is positioned within the device so that the coil is surroundedby the bone outside of the implant, for example, the coil is notpositioned within the cap of the device, the cap being locatedexternally to the bone. Additionally or alternatively, at least aportion of the coil is positioned within a portion of the cap. Forexample, between 10-25% of the length of the coil such as 15%, 18% andor intermediate lengths is positioned within a portion of the cap. Insome embodiments, the portion of the cap that comprises the coil is notsurrounded by bone, for example positioned externally to the bone. Insome embodiments, the dimensions of the coil within the cap portion maydiffer from the dimensions of the coil within the implant, for examplethe coil in the cap portion may have a larger diameter.

In some embodiments, the magnetic field through bone tissue is locatedoutside of the coil. Optionally, the coil is located within the implant,and the magnetic field is located outside of the implant.

An aspect of some embodiments of the invention, relates to a jaw-boneenhancement device for insertion into a dental implant and/or directlyinto the jawbone, the device being adapted for producing a boneenhancing electromagnetic field. In an exemplary embodiment of theinvention, the device comprises a wire wound around a core.

In an exemplary embodiment of the invention, the coiled wire is stackedaround the core. Optionally, the number of wires in the stack, thenumber of windings around the core and/or the diameter of the wire areselected according to a tradeoff between increased wire heating (e.g.,resistive heating with smaller diameter wires) and increased magneticfield (e.g., more windings produce a stronger magnetic field but requiresmall diameter wires to be able to pack the windings inside theimplant).

In an exemplary embodiment of the invention, some heat produced by thedevice is desired, for example, to improve local blood flow to the bone.For example, a temperature rise of at least 0.5 degrees Celsius in thenearby bone, or at least 1.0 degrees, or at least 2.0 degrees, or atleast 3.0 degrees Celsius. The nearby bone is, for example, the boneaffected by the electromagnetic field, for example, up to about 1 mm, orabout 2 mm, or other smaller, intermediate or larger distances. Thetemperature rise may be especially desired in the jawbone, as thejawbone is cooled off, for example, by opening the mouth. In anexemplary embodiment of the invention, the heat and the magnetic fieldsynergistically enhance osteointegration.

An aspect of some embodiments of the invention relates to a boneenhancement device, the device comprising a transmitter for producing amagnetic field to enhance surrounding bone. In an exemplary embodimentof the invention, the transmitter is activated or turned off orprogrammed by application of an external magnetic field to activate amagnetic switch.

In an exemplary embodiment of the invention, the transmitter forproducing the magnetic fields and the receiver for receiving signalsfrom the external magnetic fields share the same coil. Alternatively,the transmitter and receiver are different elements.

In an exemplary embodiment of the invention, the signal received by thecoil is sensed by an input on the controller. If the signal is above apredefined threshold (e.g., voltage), a state change is trigger. If thesignal is below the threshold, a state change is not triggered.

In an exemplary embodiment of the invention, an attenuator attenuatessignals produced by the coil. Optionally, the attenuator allows somesignals to pass to the controller and prevents some signals fromreaching the controller, for example, to prevent unwanted controlleractivations during electromagnetic field production. In an exemplaryembodiment of the invention, the attenuator is in electricalcommunication between the coil and the controller input. Optionally, theattenuator comprises one or more resistors. Optionally, the value of theattenuator is selected so that signals produced due to the coilinduction from the external magnetic field are above the threshold (andso trigger the state change). Optionally or additionally, the value ofthe attenuator is selected so that signals produced from the controlleroutput (e.g., driving the coil to produce the enhancement magneticfield) are below the threshold (e.g., to prevent self triggering).

In an exemplary embodiment of the invention, an external cradlecomprises an external transmitter for activating the controller.Optionally, the external transmitter is arranged to have a central holebig enough to fit the enhancement device. Optionally, the cradleperforms one or more functions, for example; testing the power level ofthe device, activating the device, programming the device, turning offthe device. Optionally, the device is activated while still in thesterile package.

An aspect some embodiments of the invention relates to an energy savingcircuit to provide a current to a coil to produce the enhancingelectromagnetic field. In an exemplary embodiment of the invention, thecircuit is designed to save energy in circuits having very short dutycycles, when the ratio between the time of the voltage swings and thetime of maintaining the stable voltage is, for example, 1:750-1:5000, or1:1500 to 1:2400, or 1:2000 to 1:2400, or other smaller, intermediate orlarger values are used.

In an exemplary embodiment of the invention, device operates with thelow duty but is still effective in bone enhancement.

In an exemplary embodiment of the invention, a capacitor in series withthe coil is maintained at a charge stated during a non-pulse phase. Thewait period is, for example, for about 0.001 seconds, 0.005 seconds,0.01 seconds, 0.05 seconds, 0.1 seconds, about 0.5 seconds, about 1second, about 1.5 seconds, about 2 seconds, or other smaller,intermediate or larger times. In an exemplary embodiment of theinvention, the capacitor's voltage value is swung, from the initialvoltage, to a value equal to the initial voltage but with an oppositecharge, and then back to the initial charge state.

In an exemplary embodiment of the invention, the voltage swing drives acurrent through the coil to produce the current. Optionally, the currentthrough the coil is driven by a voltage drop over the coil about doublethe initial voltage value.

In an exemplary embodiment of the invention, the peak current isobtained within one voltage swing. For example, as opposed to requiringa plurality of swings to reach the peak.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details of construction and the arrangement of thecomponents and/or methods set forth in the following description and/orillustrated in the drawings and/or the Examples. The invention iscapable of other embodiments or of being practiced or carried out invarious ways.

Exemplary Enhancement Device

FIG. 1A is a schematic of a bone enhancement device 200, in accordancewith an exemplary embodiment of the invention. In an exemplaryembodiment of the invention, device 200 comprises of a bone implantportion 202 and an optional top portion 204. In an exemplary embodiment,portion 202 is adapted for insertion into a pre-existing jaw-boneimplant 212, for example, an anchor for an artificial tooth.Alternatively, in some embodiments, portion 202 is adapted for directinsertion into bone, for example, by acting as a screw. In an exemplaryembodiment, portion 202 comprises a coil to form a bone enhancingelectromagnetic field.

In an exemplary embodiment, device 200 produces a magnetic field (shownas lines 206A-B). Optionally, the magnetic field is primarily in the phidirection, for example, parallel to the axial axis of portion 202 withinabout +/−5 degrees, or +/−15 degrees, or +/−30 degrees, or othersmaller, intermediate or larger variations from parallel. The directionof the magnetic field is related to the direction of the current througha coil located in portion 202 (detailed of coil are described herein),and in some embodiments, is reversed.

In an exemplary embodiment of the invention, the electromagnetic fieldenhances the bone remodeling and/or bone formation process. It ishypothesized that the electromagnetic field increases the activity ofosteoblasts and/or osteoclasts, for example, to remove old and/ordamaged bone and/or deposit new bone (e.g., bone turnover). In anexemplary embodiment of the invention, the electromagnetic field helpsin osteointegration, in the attachment of bone implant 212 to thesurrounding bone (e.g., trabecular bone 210). Optionally oralternatively or additionally, the electromagnetic field helps inosteointegration of bone implant 212 to surrounding cortical bone 208.It is hypothesized that the electromagnetic field reduces the time forintegration of implant 212, for example, from about 3-6 months to about1-2 months. It is further hypothesized that the electromagnetic fieldallows attachment of implant 212 to surrounding bone 210 in patientswith poor bone quality, for example, by increasing the quality of thebone (e.g., bone density).

In an exemplary embodiment, top portion 204 houses batteries, circuitryand/or other control components. Optionally, portion 204 remains outsidethe bone (e.g., at least in part). Additional details of portion 204 areprovided, for example, with reference to FIGS. 4A-4C.

In some embodiments, the enhancement device is coated with one or moredrugs. Optionally, bottom portion 202 and/or an external sheath designedfor direct insertion into bone is coated. Not necessarily limitingexamples of drugs include; osteointegration enhancement drugs,antibiotics, cellular nutrients, anti-osteoporosis medications,vasodilators.

FIG. 2 is an illustration of a bone enhancement device 1308 to enhanceintegration of implant 1306 in jaw bone 1302 (e.g., mandible ormaxilla), in accordance with an exemplary embodiment of the invention.In an exemplary embodiment, device 1308 produces magnetic fields (e.g.,shown as lines 1310A-B). Optionally, the field acts on surrounding bone1304. Optionally, the enhanced bone improves integration of implant 1306into mandible 1302. Optionally, device 1308 is removed and replaced withan artificial tooth.

In some embodiments, two or more devices 1308 are implanted side byside, for example, to replace two teeth. Optionally, the implants aresufficiently far apart so that the therapeutic region of the magneticfields do not overlap. Alternatively, the implants are close enough sothat the magnetic fields overlap. Potentially the overlap in themagnetic field provides additional bone enhancement to the thin boneregion.

FIG. 1B is a block diagram of a bone enhancement system 240, inaccordance with an exemplary embodiment of the invention. System 240 isbriefly described in broad terms, the details of which will be describedherein. In exemplary embodiment of the invention, the device is screwedin to the bone implant, for example, after the implant has been insertedinto the bone. FIG. 14 (described below) shows some CT images of theexemplary device inserted in the bone implant.

In an exemplary embodiment of the invention, different enhancementdevices are available to fit different standard implant designs. Forexample, devices are designed in different sizes and/or shapes to fitthe different implants. Alternatively, an adaptor is available to allowthe enhancement device to be compatible with the different designs.

In an exemplary embodiment of the invention, device 200 comprises a coil224 to generate an electromagnetic field 236 to enhance surrounding bone226.

In some embodiments of the invention, an optional controller 232controls application of current through coil 224. An optional powersaving circuit 230 utilizes a power source 234 (e.g., batteries) in anenergy efficient manner to control the current through coil 224 togenerate field 236. Potentially, circuit 230 reduces the energyconsumption, allowing device 200 to operate for longer periods of time.Optionally, controller is programmable, for example, by the physician.Alternatively or additionally, the physician selects a preset controllerfrom a set of controllers according to the selected treatment.

In an exemplary embodiment of the invention, device 200 is activatedwhen needed, for example, before insertion into the patient. Optionally,device 200 is activated by triggering a magnetic switch 228. Optionally,switch 228 turns controller 232 on (e.g., changes from sleep state toactive state). Optionally or additionally, switch 228 turns off device200, for example, by turning off controller 232.

In an exemplary embodiment of the invention, switch 228 is externallytriggered. In an exemplary embodiment of the invention, an externallyapplied magnetic field 238 triggers switch 238. Optionally, field 238 isformed by a transmitter/receiver 222, optionally controlled by aprogrammer 220. In some embodiments, transmitter/receiver 222 detectselectromagnetic field 236 produced by an active coil 224.

Potentially, external triggering allows activation of device 200 whenneeded, allowing further saving of power. Potentially, the shelf life ofdevice 200 is increased by controlled activation. In an exemplaryembodiment of the invention, a single pulse can be applied to the jawwithout triggering activation of the device. Optionally, the attenuatoris used to select the pulse to activate the programmer, the externallyactivated pulse having enough energy to pass the attenuator, with thepulse to produce the magnetic field not having sufficient energy to passthe attenuator.

Exemplary Method

FIG. 3 is a flowchart of an exemplary method of treatment of a patientusing the enhancement device, in accordance with an exemplary embodimentof the invention.

Optionally, at box 102, a patient (e.g., human or other animal mammal)is selected for treatment by the treatment device. The patient isselected, for example, by the physician or dentist. In some embodiments,the patient is selected for an artificial tooth implant.

In an exemplary embodiment of the invention, the patient is selectedaccording to one or more bone problem indications, not necessarilylimiting examples include; poor bone quality, insufficient bone density(e.g., osteoporosis), old age. Potentially, the enhancement deviceimproves bone integration and/or healing in patients with the weakbones.

Alternatively, patients that do not suffer from bone problems may beselected for treatment. Potentially, the enhancement device reducesintegration and/or healing time.

In some embodiments, the tooth can be placed over the cap of theenhancement device while the device is working to improve boneenhancement. Optionally, the tooth cap is removed after the treatmentperiod (e.g., 2 months), the enhancement device is removed, and thetooth cap is replaced.

In an exemplary embodiment of the invention, the patient is selectedaccording to the bone site requiring enhanced healing and/orstrengthening. Optionally, the bone site requires enhancement to attachto an inserted prosthesis. For example, a dental implant (e.g., tosupport an artificial tooth) inserted into the jaw bone.

Optionally, at box 104, the device for insertion into the patient isselected. In an exemplary embodiment of the invention, the device isselected to produce a selected enhancement magnetic field in the bone.Further details of the device are, for example, provided in the section“Exemplary Device”.

Optionally, at box 106, the device is activated before insertion intothe patient. In an exemplary embodiment of the invention, the device isactivated (e.g., switched from a sleep state to an active state) by thedentist immediately before insertion by a wireless activator, forexample, as described in the section “Magnetic Switch”. Alternatively,the device is activated by the manufacturer.

In some embodiments, the device is programmed as part of the activationand/or after the activation, for example, by the wireless activator. Forexample, the strength of the magnetic field and/or the current frequencyand/or the on/off times are programmed, for example, by using the cradleas described in the section “EXEMPLARY MAGNETIC SWITCH”.

At box 108, the device is inserted into the patient. In an exemplaryembodiment of the invention, the device is inserted into a hole orhollow within an already implanted device, for example, a dental implantin the jawbone. Alternatively, the device is inserted directly into thejawbone, for example, by screwing or hammering the device into the bone.

Optionally, at 110, the enhancement effect of the device is monitored.Optionally, imaging is used to estimate the healing of bone and/or newbone formation, for example, CT or X-rays, for example, as described inthe section “Experiment”. In some embodiments, the images are comparedto one another to determine the improvement, for example, relative to apretreatment baseline.

In some embodiments, the monitoring occurs throughout the treatmentperiod, for example, after about 2 weeks, or about 4 weeks, or about 6weeks, or about 12 weeks, or other smaller, intermediate or larger timeperiods. Alternatively or additionally, the monitoring occurs at the endof the treatment period.

Optionally, at 112, the enhancement device is removed after theenhancement period (e.g., once the bone has sufficiently healed and/orreformed). For example, the device is removed from the jaw implant toallow insertion of the tooth prosthesis. Alternatively, the enhancementdevice is left in place, for example, if removal would require surgery(e.g., inside bone fixation devices).

Optionally, at 120, one or more steps are repeated, for example, if thebatteries ran out in the device but the patient requires a longertreatment period, the current device is removed and replaced. In anotherexample, if treatment is not proceeding as expected during monitoring at110, another device with different magnetic field parameters is insertedto try to improve the healing, or the same device is adjusted and/orreprogrammed with different magnetic field parameters.

Exemplary Device

FIGS. 4A-4C are isometric views of an exemplary enhancement device 300at various stages of assembly, in accordance with an exemplaryembodiment of the invention. FIG. 4D is an enlarged view of the top cap,according to some embodiments of the invention. FIGS. 5A-5C are crosssectional views of parts of the enhancement device, in accordance withan exemplary embodiment of the invention. In an exemplary embodiment ofthe invention, the enhancement device is designed to be inserted into adental implant located in the jaw bone (e.g., to secure an artificialtooth). Optionally, the device is inserted into the dental implant. Inan exemplary embodiment of the invention, the enhancement deviceproduces a magnetic field to enhance bone growth around the implant toimprove adherence of the implant to the bone. Optionally oradditionally, vibrations are produced, for example, by the core reactingto the field and/or heat.

Referring to FIG. 4A, a coil 304 is wound around a rod shaped extension302. Further details of coil 304 are described, for example, withreference to FIG. 6. Optionally, a printed circuit board 308 is disposedat a proximal end of extension 302. Optionally, on one side of board 308(e.g., closer to extension 302) are electrical components 306, forexample, resistors, capacitors and/or transducers. Optionally, on theopposite side of board 308 is disposed a controller 310. Circuitdiagrams detailing the interactions between controller 310, components306 and coil 304 are described, for example, with reference to FIGS. 9and/or 11. In an exemplary embodiment of the invention, one or morebatteries 312 are disposed next to controller 310. Optionally, batteriesare encased in a cylindrical contact 314. In an exemplary embodiment ofthe invention, the batteries are selected to last until the device canbe replaced with the permanent implant, for example, at least 30 days,at least 50 days, at least 70 days, at least 100 days, or other smaller,intermediate or larger time frames. In a not necessarily limitingexample, there are two batteries, each producing about 1.55 Volt (for atotal of about 3 Volt), or the total voltage ranges from about 1.2Volt-3.2 Volt, and/or the batteries have a rated capacity of about 8.3mAh, or about 5 mAh-10 mAh, or other smaller, intermediate or largervoltages and/or capacities are used.

In some embodiments, rod shaped extension 302 comprises a separate unit,for example not connected directly to other components such ascontroller 310 and/or electrical components 306 and/or batteries 312.Optionally, coil 304 within rod 302 acts both as a transmitter of themagnetic field and as a receiver of the activation signals. In anexemplary embodiment, an externally applied magnetic and/orelectromagnetic field is applied from a distance, for example activatinga switch which enables the passing of a current pulse through coil 304.Optionally, the magnetic field activates controller 310, which controlsthe current passing through coil 304. Optionally, in such a case, rod302 comprising coil 304 is implanted in a bone on its own, while othercomponents of the device such as controller 310 and/or batteries 312 arepositioned externally to the bone, for example outside the mouth.Alternatively, in some embodiments, rod shaped extension 302 andbatteries 312 are connected directly, and controller 310 remotelyactivates the coil within rod shaped extension 302 and/or the batteriesfrom a distance, for example turning the device on or off. In someembodiments, controller 310 charges batteries 312 by wirelessconnection.

FIG. 4B illustrates the partly assembled device of FIG. 4A, fitted witha bottom cap 318. Extension 304 with wound coil 302 is placed insidebore of cap 318. In an exemplary embodiment of the invention cap 318comprises an outer screw 316. Optionally, screw 316 is adapted forthreading inside an implant, for example, the dental implant.Alternatively or additionally, in some embodiments, coil 304 is wrappedaround screw 316.

FIG. 4C illustrates the final assembled enhancement device 300. Thepartly assembled device of FIG. 4B is fitted with a top cap 320 (e.g.,fits over batteries 312). An enlarged view of top cap 320 is shown inFIG. 4D. Optionally, top cap 320 is joined to bottom cap 318 by bottomcap threads 322 (shown in FIG. 5A) and matching top cap threads 334(shown in FIG. 4D and in FIG. 5B). In some embodiments, the threadingwhich connects the top and bottom caps is opposite to the threading ofscrew 316 into the bone. For example, the threading direction of the topand bottom caps is counterclockwise, and the threading direction ofscrew 316 is clockwise. A potential advantage of the opposite threadingincludes preventing disengagement of the top and bottom caps outside thedental implant during threading of screw 316.

In an exemplary embodiment of the invention, device 300 comprises ashaft 340 and a cap 342. As described, shaft 340 is inserted into thebone implant, and is surrounded by bone when deployed. Optionally, cap342 is located outside of the implant and outside of the bone.Optionally, cap 342 has a size similar to a tooth to fit betweenadjacent teeth in the patient's mouth. In a not necessarily limitingexample, shaft 340 is designed to fit into a standard bone implanthaving an external diameter of, for example, about 3.4-3.7 mm, aninternal diameter of, for example, about 1.2 mm, an external height of,for example, about 10-11 mm and an internal height of, for example,about 7.8 mm.

FIG. 5A is a cross section of bottom cap 318. In an exemplary embodimentof the invention, cap 318 comprises screw 316 having a bore 324 thereinsized to fit extension 304 and coil 302. Optionally, cap 318 compriseschamber 328 to house one or more control components. Optionally, printedcircuit board 308 is secured in position on a flange 330.

FIG. 5B is a cross section of top cap 320. In an exemplary embodiment ofthe invention, cap 320 contains a release port 332 to allow insertionand/or removal of device 300 from the bone implant. Optionally, port 332is hexagonal shape to allow rotation of screw 316 by a suitably shapedtool (e.g., commonly available). Optionally, port 332 comprises aninternal thread.

Additionally and/or alternatively, in some embodiments, a face of cap320 such as the top face is shaped to engage a tool, for example havinga hexagonal shape which may be engaged by a suitably shaped tool, forexample a socket wrench. Optionally, the shaped top face limits the needfor an additional element for engaging a tool, therefore a shorter capmay be used. In some embodiments, the top face of cap 320 comprises anexternal thread.

In an exemplary embodiment of the invention, bottom cap 318 and/or topcap 320 are made from a biocompatible material, for example, titaniumalloy. In an exemplary embodiment of the invention, the material isselected to have a relatively low conductivity (e.g., as compared toother metals) to reduce the formation of eddy currents therein.

FIG. 5C is a cross section of enhancement device 300, according to someembodiments of the invention. In some embodiments, as previouslydescribed, the device includes batteries 312, controller 310, a coil 304wound around rod shaped extension 302, and electrical components 306. Insome embodiments, as previously described, top cap 320 comprises a port332.

In some embodiments, coil 304 extends along rod shaped extension 302. Insome embodiments, coil 304 extends within a portion of the cap.

In a not necessarily limiting example, the size of cap 320 designed tofit in a jaw implant and between teeth has an external diameter 360 of,for example, about 5.8 mm and a height 362 of, for example, about 5-6mm. In some embodiments, the size of external diameter 360 rangesbetween 3-7 mm, for example 3.5, 4.2, 6.1 mm or intermediate sizes. Insome embodiments, the size of height 362 ranges between 3-8 mm, forexample 3.2, 5.5, 7.8 mm.

Exemplary Device Parameters

Referring back to FIGS. 4A-4D, in an exemplary embodiment of theinvention, current through coil 302 produces an electromagnetic field inthe surrounding bone. Inventors discovered device designs that producean electromagnetic field that enhances bone, for example, reduces theamount of time that a dental implant requires to be secured in the jawbone.

FIG. 6 illustrates the discovered design of wound coil 304. In anexemplary embodiment of the invention, wound coil 304 comprises a wire352 wound around a core 350. In an exemplary embodiment of theinvention, wire 352 is wound around the circumference of core 350.

In an exemplary embodiment of the invention, the wire is made fromelectrically conductive materials, for example, copper, silver,aluminum, gold.

In an exemplary embodiment of the invention, the wire parameters are:

-   -   Wire diameter of, for example, about 10-80 micrometers, or about        10-20 micrometers, or about 40-80 micrometers, or about 10-40        micrometers, or other smaller, intermediate or larger diameters.    -   Stacked layers of the wire when wound around the core, for        example, 1-10 layers, or about 2-6 layers, or about 4-5 layers,        or other smaller, intermediate or larger number of layers.    -   Each of the stacked layers has, for example, about 100-150 turns        around the core, or about 125-133 turns, or other smaller,        intermediate or larger numbers of turns. In an exemplary        embodiment, the turns are arranged along the long axis of the        core. In an exemplary embodiment of the invention the total        number of wire turns is, for example, about 300-600, or about        450-550, or other smaller, intermediate or larger number of        turns.    -   The diameter of the coil (e.g., when wound around the core) is,        for example, about 0.5-1.5 mm, or about 0.8 mm to about 1.15 mm,        or other smaller, intermediate or larger diameters.

Inventors discovered that the stacked coiling design produced a magneticfield that enhances the osteointegration of the implant in bone, forexample, as described below in the section “EXPERIMENT”.

In an exemplary embodiment of the invention, the device is programmed toproduce a desired amount of heat. Alternatively or additionally, thedevice is built to have a certain heat output. Optionally, the heatgenerated by resistive heating of the coil is controlled and/orselected. Optionally, the temperature in the bone around the tissue israised to a preselected value at a steady state of operation, forexample, to no more than about 0.02 degrees Celsius, or no more thanabout 0.1 degrees, or no more than about 0.2 degrees, or no more thanabout 0.3 degrees, or no more than about 0.5 degrees Celsius, or no morethan about 1.0 degrees, or no more than about 1.5 degrees, or no morethan about 2 degrees, or no more than about 3 degrees, or other smaller,intermediate or larger temperature rises. Optionally, the temperature israised in the bone within about 1 mm of the implant surface, or about 2mm, or about 3 mm, or other smaller, intermediate or larger dimensions.

To help with understanding of the resistive heating, a short explanationof the underlying theory is provided. Even if the theory is incorrect,it does not preclude the working of embodiments of the invention asdescribed. Note that the explanation relates to the exemplaryembodiment, and may not be accurate for other embodiments.

The coil resistance R is related to the wire radius a, winding radius rand number of turns N by:R=ro*N*2πr/(pi*a^2)

Where ro is the resistivity of the coil wire material.

The dissipated heat W_(J) is given byW _(J) =R∫I(t)² dt

Where R is the resistance, I is the current, and the integration is overthe pulse duration.

The equations show that the magnetic field intensity is independent ofthe wire diameter, as long as the packing volume and energy consumptionare the same. However, the wire diameter and number of turns affect theresistive loss and heating. Inventors estimate that if using a coil with532 turns and wire diameter of 40 μm, and applying a current at afrequency of 10 Hz, the heating rate is less than about 0.02° C. insteady state operation. In this case, the overall coil impedance is muchmore affected by the ferromagnetic core response to the eddy currents.

In an exemplary embodiment of the invention, the coil design accountsfor the desired overall inductance of the coil and/or ferromagnetic corecomplex. Potentially, a wide range of wire diameters and/or number ofturns may be used.

Inventors estimate that using the wire diameter of 10 μm and repetitionrate of 10 Hz, the heating rate may reach 0.3° C. in steady stateoperation.

In an exemplary embodiment of the invention, heating is reduced.Alternatively, heating is elevated. For example, the design is selectednot to go over a temperature of, for example, about 2 degrees Celsiusduring steady state operation, or about 1.5 degrees Celsius, or about 1degrees Celsius, or about 0.5 degrees Celsius, or other smaller,intermediate or larger temperatures.

In an exemplary embodiment of the invention, the heat from operation ofthe device and the produced magnetic fields cause a synergistic effecton bone enhancement. Optionally, a small amount of heat is selectivelyintroduced into the surrounding tissue. Inventors hypothesize that theheating helps improve the bone enhancing effects, for example, byincreasing blood flow to the bone region next to the implant.

Some embodiments of the enhancement device are especially good for thejaw, because the produced heat helps offset cooling of the device and/orsurrounding bone, for example, conductive cooling caused by opening ofthe mouth and introduction of cooled air around the implant. Withoutbeing bound to theory, the magnetic fields improve bone turnover and/orformation, with the heat helping to increase blood flow and bring theneeded raw materials and/or remove waste from the bone enhancement siteare faster rates. However, some embodiments of the device can also beused in other items, for example, orthopedic devices such as nailsand/or plates (e.g., for fracture fixation). Optionally, the orthopedicdevices comprise a hollow inside, and the head of the enhancement deviceis the same diameter as the hollow, for example, so that the enhancementdevice is insertable therein. Optionally, the enhancement device iseasily removable from the body, for example, there are wires extendingfrom the enhancement device to outside of the body.

Inventors discovered that wrapping the coil around a ferromagnetic coreprovides for the bone enhancing magnetic field. For example, when usingsettings according to the exemplary embodiment, use of the coreincreases the magnetic flux density at a distance of about 2 mm from theouter device edge by about 5-10 fold, or by about 6-7 fold, or othersmaller, intermediate or larger values.

In an exemplary embodiment of the invention, core 350 is made from aferromagnetic material. Not necessarily limiting examples include;ferrite, iron, iron powder, laminated silicon steel, amorphous metals orany other type of suitable ferromagnetic material.

In an exemplary embodiment of the invention, the length of the ferriteis sized to fit into the interior of the screw portion of the bottomcap, for example, about 5-10 mm, or about 6-8 mm, or about 5.5-7.5 mm orother smaller, intermediate or larger sizes. Optionally, the core issized according to available space in the implant, which in someembodiments reaches the tip of the implant and in some embodiments doesnot.

In an exemplary embodiment of the invention, the diameter of the ferriteis sized to fit into the interior of the screw portion of the bottomcap, for example, about 0.5-1.0 mm or about 0.6-0.75 mm, or othersmaller, intermediate or larger sizes.

In an exemplary embodiment of the invention, the effective magneticpermeability (e.g., relative permeability, or μ_(r)) is, for example, atleast 40, or at least 100, or at least 500, or at least 1000, or othersmaller, intermediate or larger values. Inventors hypothesize that arelatively higher magnetic permeability will produce a relatively highermagnetic flux density.

Inventors discovered that the cap surrounding core 350 (e.g., cap 318made from titanium) increases eddy current formation in core 350, whichis hypothesized to increase the effective impedance of coil 304. In anexemplary embodiment of the invention, the conductivity of core 350 isrelatively reduced. Optionally, core 350 is processed, the processingpotentially reducing the conductivity. In a not necessarily limitingexample, core 350 is laminated (e.g., formed into thin layers separatedby an insulating material, the layers arranged parallel to the directionof the expected magnetic flux lines). Inventors hypothesize thatlamination of core 350 also reduces the eddy currents induced in core350. In some cases, different materials are used for cap 318 to reduceeddy current formation.

In exemplary embodiment of the invention, to achieve the desiredoperation frequency, the capacitance and resistance in the circuit areselected according to the coil effective inductance and theferromagnetic core. Note that the inductance is hypothesized to beaffected by the ferromagnetic core and by the operation frequency. Thegeneral relation between the actual operation frequency f_(act) and theinductance L, resistance R and capacitance C is given by:

$f_{act} = \frac{1}{{2\;\pi\sqrt{\frac{1}{LC}}} - \frac{R^{2}}{4\; L^{2}}}$Exemplary Magnetic Field Parameters

In an exemplary embodiment of the invention, the coil producing themagnetic field is wound around the central axis of the enhancementdevice. To help understand the magnetic field produced by theenhancement device, the following cylindrical coordinates system isused:

Axial axis—An axis parallel to the implant top-down axis. Fieldcomponent along this axis is termed “z component”.

Radial axis—The radius vector from a point on the implant axis outward.Field component along this axis is termed “r component.”

Phi axis—An axis tangential to the radius vector at any point. Fieldcomponent along this axis is termed “phi component”.

In an exemplary embodiment, the enhancement device is inserted inside adental implant previously positioned inside the upper or lower jawbones. To help understand locations relative to the jaw bone, thefollowing terms are used:

“cervical”—along a line between the upper and lower jaws, and moreparticularly, along a line between the implant root and a covering ofthe implant device;

“coronal”—along a cervical line, toward the implant device covering;

“apical”—along a cervical line, toward the implant root; and

“radial”—along a line generally coinciding with the radius of thesubstantially circular implant device, or along a line parallel to aline generally coinciding with the radius of the substantially circularimplant device, and substantially perpendicular to a cervical line.

In an exemplary embodiment of the invention, the coil having circularwindings around the central axis of the device axis induces magneticfield mainly along the axial axis (z component), and a radial componentaround the coil top and bottom edges. The induced electric field willhave mainly a phi component.

The terms described above are not necessarily limiting, but are used tohelp understand the described embodiment. Other embodiments may requireother reference terms.

FIG. 7A is a graph of one example of an enhancing magnetic field,illustrating the discovery by the inventors of magnetic field parametersthat cause acceleration in the bone regeneration process (e.g.,osteogenesis) around the implant (e.g., dental implant), for example, asdescribed in the section “EXAMPLES”. FIG. 7B is an illustration of anexemplary bone enhancement device 200 creating the field illustrated inFIG. 7A. FIG. 7C is the raw data in table format used to draw the graphof FIG. 7A.

In an exemplary embodiment of the invention, the device is constructedso that it generates a magnetic field with the combination of thefollowing properties:

Magnetic flux density is, for example, about 0.05-0.5 milliTesla (mT) atup to about 2 mm from the surface of the device, or for example, about0.2-0.45 mT, or for example about 0.2-0.3 mT, or other smaller,intermediate or lager values at up to about 2 mm. For example, magneticflux density of, for example, about 0.05-0.5 mT at up to about 1 mm fromthe surface of the device, or for example about 0.2-0.45, or for exampleabout 0.2-0.3 mT, or other smaller, intermediate or larger values at upto about 1 mm.

In an exemplary embodiment of the invention, the magnetic flux densityis located around at least, for example, about 90% of the length of theimplant, or at least about 80% of the length, or at least about 70% ofthe length, or at least about 60% of the length, or at least about 50%of the length, or other smaller, intermediate or larger percentages.Alternatively or additionally, the magnetic field density is located ata jaw-bone depth (e.g., from the surface) of, for example, up to atleast about 3 mm, or 4 mm, or 5 mm, or 7 mm, or 10 mm, or 13 mm, orother smaller, intermediate or larger depths. In an exemplary embodimentof the invention, the enhancement device is constructed and/or built tohave the magnetic field flux density as mentioned above.

In an exemplary embodiment of the invention, the implant is cylindricalin cross section. In other embodiments, other shapes are used, forexample, a square cross section.

In an exemplary embodiment of the invention, the magnetic fields linesprimarily parallel to the long axis of the cylindrical implant. Forexample, not considering the direction of the magnetic field around thepoles.

In an exemplary embodiment of the invention, the length of the implantproducing the enhancing magnetic field is in contact with trabecularbone. Optionally or alternatively or additionally, the length is incontact with cortical bone.

In an exemplary embodiment the current pulse to produce the magneticfield has the following combination of parameters (optionally togetherwith the magnetic field parameters):

Frequency of, for example, 0.5 Hz to 50 Hz, for example, from 10 Hz to40 Hz.

Pulse duration of, for example about 12 microseconds to about 70microseconds, or about 30 to 70 microseconds, or about 45 to 55microseconds, or other smaller, intermediate or larger pulse durations.Optionally, the pulse is biphasic, for example comprised of a positivesignal followed by a negative signal.

Repetition rate of the pulse, for example, continuously operating,single pulse, multiple pulses (e.g., preset number), or other repetitionrates.

A duty cycle ratio (e.g., pulse duration as a ratio to one period, or1/frequency) of, for example, about 1:1500-1:2400, or about1:2000-1:2400, or other smaller, intermediate or larger duty cycles.

Peak to peak current amplitude of, for example, about 50-150 mA or about50 mA-130 mA, or about 50-80 mA, or other smaller, intermediate orlarger peaks.

Average pulse current of, for example, about 30-80 mA, or about 40-50mA, or other smaller, intermediate or larger values.

Average current of about 3-15 mA, or about 5-10 mA, or other smaller,intermediate or lager values.

Pulse waveform, for example, sinusoidal, square, sawtooth, triangular.

In some embodiments, the current is continuously applied for a periodof, for example, about 30-70 days, or about 50-70 days, or othersmaller, intermediate or larger time values. Alternatively, the currentis turned on and off during set times, for example, turned on at nightbefore sleep and/or turned off upon waking up.

In an exemplary embodiment of the invention, the electrical field at thebone site within about 2 mm of the enhancement device is, for example,about 0.5-6 mV/cm, or about 1 to 4 mV/cm, or other smaller, intermediateor lager values.

In one example, the following set of parameters are used: a biphasic,sinusoidal current pulse of 50 microseconds produces the magnetic filearound the implant. The current is produced with a peak to peakamplitude of about 130 mA. The pulse is followed by a wait period whichis about 2000 times as long as the current pulse (for a total time of0.1 seconds). The pulse and corresponding wait time are continuouslyrepeated (e.g., frequency of Hz) for at least 50 days.

Energy Saving Mechanism

In an exemplary embodiment of the invention, one or more energy savingmechanisms are used. Optionally, an energy saving circuit is used.Optionally or additionally, the device is only activated when needed.Potentially, the energy saving mechanisms allow for the device tooperate for the entire treatment duration, for example, at least 30days, or at least 50 days, or at least 70 days, or other smaller,intermediate or larger time periods without replacing the power source.Potentially, the energy saving mechanisms allow for the use of smallbatteries that can fit inside the enhancement device and that will allowthe device to operate for the treatment duration.

Energy Saving Circuit

FIG. 8A is a simplified circuit diagram of the energy saving circuitcomprising a coil 1402 (e.g., to generate the bone enhancing magneticfield) and a capacitor 1404 (e.g., to form a resonance circuit). FIG. 8Bshows the current through coil 1402 during different circuit states ofFIG. 8A. FIG. 8C shows the voltage of capacitor 1404 during differentcircuit states of FIG. 8A.

In an exemplary embodiment of the invention, the energy saving circuitdrives a current through coil 1402 (to create the enhancing magneticfield), effectively forming a voltage drop across coil 1402, the valueof the voltage drop being about double the voltage provided by thevoltage source. In a not necessarily limiting example, the voltageprovided by the power source (e.g., one or more batteries) is, forexample, about 3.0 Volt, for example, each battery produces about 1.5Volt.

Without being bound to theory, the energy saving circuit can be thoughtof as a pendulum able to maintain a high amplitude by providing a smallamount of energy (e.g., push) on each swing as opposed to requiringmultiple swings to get to the high amplitude during a time periodrequired for the cycle. For example, before the start of the pulse, thependulum is in the position having an amplitude above a reference. Theamplitude represents potential energy of the pendulum, similar to thepotential energy stored in the capacitor in the form of charges (e.g.,Volts). To generate the pulse, the pendulum is released to swing. Theenergy of the moving pendulum represents the energy released by thecapacitor in the form of the current through the coil. The returningpendulum will reach an amplitude slightly lower than the originalrelease amplitude (e.g., due to energy losses such as friction and/orkinetic energy harnessed from the swing). To raise the pendulum back tothe original amplitude, only a small amount of additional energy isrequired, for example, as compared to moving the pendulum from anamplitude of zero (e.g., no stored potential energy state).Correspondingly, only a small amount of charge needs to be added to thecapacitor as opposed to a complete recharge. The pendulum is heldstoring the potential energy until the next release to generate the nextpulse.

In an exemplary embodiment of the invention, the coil is not efficientin transmitting, so the energy not transmitted is collected and/orstored for use during the next transmission.

In an exemplary embodiment of the invention, the energy saving circuitsaves energy when current is applied using very short and/or a smallnumber of pulses followed by a long wait, for example, the ratio of thecurrent pulses to the wait time is, for example, about 1:750 to about1:5000, or about 1:2000 to about 1:2400, or other smaller, intermediateor larger values.

For comparison purposes, in an embodiment without the energy savingcircuit, to reach the peak to peak current value of about 130 mA, one ormore charging current pulses are applied (or using the pendulum concept,smaller swings). Due to the very short duty cycle, the charging currentsare needed to reach the peak current values through the inductor. In onenot necessarily limiting example, the peak of the charge current pulses(e.g., half sinusoid wave) in succession are: +22 mA, −29 mA, +36 mA,−42 mA, +50 mA, −57 mA until the peak values of +65 mA and −65 mA arereached. Without being bound to theory, the energy saving circuiteliminates the need for the charging pulses.

Referring back to FIGS. 8A-C, the capacitor is maintained charged to thehighest voltage capable by the batteries (e.g., shown in a notnecessarily limiting manner as +4.1 V, for the 3.0 Volt total capacity).The charged state of the capacitor can be through of as the pendulumheld at the highest amplitude. The positive charged state is referred toas state 3.

To create the current pulse through coil 1402, a switch 1408 connectscapacitor 1404 to a negative voltage source 1410 (e.g., reverse polarityof the battery, or about −3 V), also referred to as state 1. As shown inFIG. 7C, the voltage across capacitor 1404 swings from the positive tothe negative highest voltage values (e.g., from +4.1 Volt to −4.1 Volt).Correspondingly, the current through coil 1402 rises from 0 to thehighest current value (e.g., +65 mA according to the circuitparameters). The state change can be through of as the pendulum swingingfrom one amplitude to the other side.

Switch 1408 causes a change from state 1 to state 2, connectingcapacitor 1404 to the positive voltage source 1412. Capacitor 1404swings back from the lowest negative voltage to the highest positivevoltage (e.g., from −4.1 Volt to +4.1 Volt). Correspondingly, thecurrent through coil 1402 falls from 0 to the lowest current value(e.g., −65 mA). The effective current through coil 1402 is the sum ofthe absolute value of the highest and lowest values (e.g., 65+65=130mA). The current provides the bone enhancing electromagnetic field. Thestate change can be through of as the pendulum swinging back from theother side to the original position. Switch 1408 causes a change fromstate 2 back to state 3, removing capacitor 1404 from any voltagesource, and trapping the highest voltage value in capacitor 1404 (e.g.,+4.1 Volt). Capacitor 1404 is held in state 3 until the next scheduledpulse. The state can be through of as the pendulum held in the originalposition with the original amplitude, ready for another release.

In some embodiments, the enhancement device is programmed to improveenergy efficiency. Optionally, the device is programmed to only functionduring the night, for example, in patients that sleep with their mouthsclosed, the mouth does not cool and energy is preserved. Alternatively,the device is programmed to function only during the day, for example,in patients that sleep with their mouths open, the energy consumptionwould increase due to the cooling effect of the air in the mouth.

Exemplary Magnetic Switch

FIG. 9 is a simplified diagram of a circuit having a magnetic switch, inaccordance with an exemplary embodiment of the invention. Optionally,the magnetic switch activates a controller 602. Optionally, controller602 controls a magnetic field transmitter (e.g., a coil 614) to emit theenhancement magnetic field. A potential advantage of the magnetic switchis selective remote activation to preserve battery life, for example, toprovide a relatively long shelf life and/or only activate the devicewhen needed.

In some embodiments, the magnetic switch can be used with other implanttypes, for example, devices adapted for insertion into bone and/or boneimplants, for example, orthopedic devices, for example, to enhance bonefixation, and/or fracture healing. Potentially, the same advantagesapply, for example, of preserving battery life.

In an exemplary embodiment of the invention, controller 602 isprogrammed. Optionally, controller 602 arrives unprogrammed (e.g., fromthe manufacturer) and is programmed before insertion. Alternatively, theprogramming is done to adjust one or more stored parameters (e.g.,stored on a memory coupled to the controller). Some not necessarilylimiting examples of programming options include; pulse frequency, pulseduration, amplitude of magnetic field, how often to leave on magneticfield (e.g., turn on only at night and turn off during the day).Optionally, controller 602 can be turned off (e.g., to sleep state).

In an exemplary embodiment of the invention, the programming is done bythe externally applied magnetic field. Optionally, the magnetic field iscoded (e.g., by variations in wait time between pulses), and thecontroller decodes the message to program itself.

In an exemplary embodiment of the invention, the magnetic switch isactivated by an externally applied magnetic field. Optionally, theremote signals are received on the same coil that is used to generatethe bone enhancing electromagnetic field.

In an exemplary embodiment of the invention, the circuit comprises anattenuator 612 to prevent self activation of controller 602, forexample, during normal operation of the device to produce the magneticfield.

In an exemplary embodiment of the invention controller 602 producesoutput signal 604, for example, as described herein. Optionally, anoutput buffer 608 filters the output signal. In an exemplary embodiment,a resonance capacitor 610 is used to control the frequency of magneticfield produced by coil 614.

In an exemplary embodiment of the invention, controller 602 is placed ina sleep mode. For example, consuming no more than about 10 nA, or 20 nA,or 30 nA, or 50 nA, or 100 nA, or other smaller, intermediate or largercurrents. The low currents are possible using the energy saving circuit,for example, as described with reference to FIG. 11. In an exemplaryembodiment of the invention, batteries provide controller 602 withenough power so that controller 602 is able to remain in the sleep modefor at least 1 year, at least 3 years, at least 5 years, or othersmaller, intermediate or larger time frames. In some embodiments, duringsleep mode, the controller is activated by a pulse on its reset input(“Master Clear”—MCLR input). Optionally, the magnetic switch controlsthe passing of the pulse on the reset input. Optionally, the switch isactivated by an external magnetic field. In some embodiments, during anactive operation mode, attenuator 612 prevents the MCLR input, forexample to prevent self reset of the enhancement device.

In some embodiments, controller 602 is programmed to measure timeintervals between pulses. Optionally, the time intervals are decoded toa data protocol for controlling activation and/or deactivation of thedevice.

In a not necessarily limiting scenario, the enhancement device isassembled by the manufacturer. Optionally, the device is manufacturedand shipped in a hermetically sealed packaged, for example, to ensuresterility and quality of the device. The batteries have been installedand in electrical communication with the circuitry of the device. Beforeimplantation in the patient, the device is activated (e.g., as describedherein), for example, by the treating physician and/or dentist.Optionally the device is activated when still in wrapping, potentiallypreserving the sterility of the device until insertion. Optionally, thedevice is activated by placing the device in a hole in the cradle.

In an exemplary embodiment of the invention, controller 602 is remotelyactivated by a signal received on coil 614 that is also used to producethe selected magnetic field. Optionally, coil 614 produces a voltage dueto an externally applied magnetic field. Optionally, the externallyapplied field is applied from a distance and/or without contacting coil614, for example, by the cradle as described herein. Alternatively, insome embodiments, a separate coil not used to produce the magnetic fieldis used to receive the signal. Potentially, use of the single coil totransmit and receive saves spaces and allows the circuitry to resideinside the small volume.

In an exemplary embodiment of the invention, a sufficiently strongexternally applied magnetic field produces a voltage by coil 614, thevoltage being high enough to trigger activation of controller 602 at atrigger signal input 606. Alternatively, in some embodiments, theexternal magnetic field produces a smaller signal that is then amplifiedand optionally undergoes a comparison by a comparator before enteringinput 606. Potentially, use of the strong external field does notrequire the additional components, reducing power requirements andspace.

In an exemplary embodiment of the invention, an attenuator 612 inelectrical communication between coil 614 and input 606 is selected toonly allow voltages above a voltage threshold to be transmitted to input606. Optionally, the voltage threshold is selected so that voltageshigher than the threshold trigger input 606 (e.g., will trigger a statechange). In an exemplary embodiment, the voltage threshold is selectedto be above the voltage at input 606 that is created during regularoperation of the device (e.g., generation of therapeutic magnetic fieldby coil 614). Optionally attenuator 612 is, for example, one or moreresistors, transistors, inductors and/or combinations thereof. Theresistance of the resistor is selected according to the selected voltagethreshold and according to other circuit elements, for example the valueof resonance capacitor 610. Potentially, attenuator 612 preventstriggering controller 602 during device operation (e.g., treatment).Potentially, attenuator 612 also prevents waste during regular use. Byreducing the input signals, the processor requires less energy tooperate to process the input signals.

In an exemplary embodiment of the invention, a first signal at input 606triggers controller 602 to change from the sleep mode to the activemode, the active mode allowing data processing and/or delivering thestimulating magnetic field. Optionally, a second signal at input 606triggers controller 602 to change from the active mode back to the sleepmode. Alternatively or additionally, a sequence of signals at input 606programs controller 602, for example, with magnetic field parametersand/or current parameters.

In an exemplary embodiment of the invention, the signal applied by theexternal magnetic field is encoded and is decoded by controller 602(after entering input 606). Optionally, software and/or circuitry keepscontroller 602 in the active state after each pulse received at input606 to allow decoding. In a not necessarily limiting example, the codecomprises of a set value or sequence of time intervals between pulses.Potentially, the coded signal prevents inadvertent activation and/ordeactivation of controller 602, for example, by non-intentionalexternally applied magnetic fields.

In some embodiments, controller 602 and/or another external devicecharges the battery inside the enhancement device. Optionally,controller 602 charges the batteries by wireless charging (e.g.,inductive charging), for example, by using the transmitting and/orreceiving coil.

In an exemplary embodiment of the invention, the enhancement systemcomprises a transmitter for remote activation of the electromagneticswitch. Optionally, the transmitter is in the shape of a cradle, forexample, the enhancement device is inserted into a hole and a button ispressed to activate the magnetic switch. Alternatively, the transmitteris shaped for placement inside the mouth against the tooth, for example,placed inside a soft material so that it can be bitten and secured inposition against the tooth or when the mouth is open. Alternatively, thetransmitter is placed near the implant from outside of the mouth, forexample, against the skin of the cheek.

FIG. 10A is a top view, FIG. 10B is an isometric view, and FIG. 10C is across sectional side view of a remote activator (e.g., cradle 300) foractivation of the enhancement device, in accordance with an exemplaryembodiment of the invention. Cradle 300 is designed to interact with thecircuit of FIG. 9, for example, FIG. 10C shows an enhancement device 622being activated by cradle 300.

In an exemplary embodiment of the invention, cradle 300 comprises a hole302 sized and shaped to accommodate at least some of a portion ofenhancement device 622 comprising coil 614. Alternatively, device 622 isactivated while still in package 624 (e.g., clear plastic cylindricalbox), for example, to preserve sterility of device 622 during theactivation. Optionally, some space is allowed between walls of hole 302and coil 614 and/or walls of package 624.

In an exemplary embodiment of the invention, hole 302 is surrounded by atransmitter (e.g., coil 620), and/or the transmitter is to the side ofhole 302. Current flowing through transmitter coil 620 induces amagnetic field inside hole 302. The induced magnetic field induces avoltage sufficiently high voltage across coil 614 to activate controller602, for example, as described with reference to FIG. 9.

In an exemplary embodiment of the invention, coil 620 around hole 302 isused to detect the state of the enhancement device, for example, if thedevice is functioning or not. Optionally, if coil 614 is producing thetherapeutic magnetic field, a current through coil 620 around hole 302is detected. Alternatively, if coil 614 is not producing the therapeuticmagnetic field, there is no current through hole coil 620.Alternatively, the correct function of therapeutic device 622 inproducing the therapeutic magnetic field is detected according to themagnitude and/or pattern of the induced current through hole coil 620.

In some embodiments, the cradle is used to test the power levelgenerated by the implant. Optionally, the power level is just measured.Alternatively, the device is optionally first turned on by the cradle,the power level is measured by the cradle, and then the device isoptionally turned off by the cradle.

In an exemplary embodiment of the invention, input 306 (e.g., button,microphone for voice activation) allows for the user to control theactivation of the enhancement device. Optionally, pressuring button 306powers coil around hole 302 and changes the state of the enhancementdevice, for example, from sleep to active. Optionally or additionally, asecond press re-activates coil around hole 302 and changes the state ofthe enhancement device again, for example from active back to sleep.

Alternatively, no input is provided, with activation/deactivationoccurring automatically by cradle 300 upon insertion of the enhancementdevice into hole 302.

In an exemplary embodiment of the invention, output 304 (e.g., LED,speaker for audio output) allows the user to determine the state of theenhancement device. Optionally, the sleep state of the enhancementdevice is indicated. Optionally or additionally, the active state of theenhancement device is indicated. Optionally or additionally, the powerstatus of cradle 300 is shown, for example, if cradle 300 is plugged inand/or batteries are providing sufficient power for operation.

In some embodiments, cradle 300 comprises a communication link (e.g.,wireless and/or wired, e.g., USB) to a computer terminal (e.g., laptop,remote server, internet web site). Optionally, programming of theenhancement device is provided through software on the computerterminal, with uploading and downloading to the enhancement deviceprovided through cradle 300. Optionally or additionally, cradle reads anID code from the device for billing purposes. Optionally oradditionally, the cradle reports activity via the internet, USBconnection, or other communication channels. Optionally or additionally,the cradle is connected to a computer to provide a programminginterface.

Exemplary Circuit

FIG. 11 is an exemplary circuit diagram, illustrating the control of theformation of the magnetic field with the optional energy saving designs.

In an exemplary embodiment of the invention, U1 is a controller tocontrol application of current to the coil to form the enhancementmagnetic field, for example, as described herein. U1 is connected toground through Vss and to batteries through Vdd. Optionally, U1 is avery low power consumption controller, for example, consuming no morethan about 30 nA in sleep mode and/or 500 nA in active mode betweenpulses. In some not necessarily limiting examples, U1 is implemented asan application specific integrated circuit (ASIC), or general circuitryprogrammed by software.

In an exemplary embodiment of the invention, L1 is a coil that providesthe therapeutic electromagnetic field when current is provided throughthe coil.

In an exemplary embodiment of the invention, L1 is in series withcapacitor C2.

In an exemplary embodiment of the invention, voltage at Vout isconnected to either RA0 (positive voltage) or by RA5 (negative voltage).Optionally, switches Q1 and Q2 control the state changes of C2, forexample, as described in the section “Energy saving circuit”.Optionally, state 3 is achieved by Q1 and Q2 being off. Optionally oradditionally, state 1 is achieved by activation of Q1. Optionally oradditionally, state 2 is achieved by deactivation of Q1 and activationof Q2. In one example Q1 and/or Q2 are implemented as transistors, forexample, field effect transistors (FET).

In an exemplary embodiment of the invention, R2 is in parallel with C2.Optionally, R2 acts as the attenuator described in the section “MagneticSwitch”. In an exemplary embodiment of the invention, R2 and C2 serve asa resonance circuit to generate the required frequency through L1.Optionally, the values of R2 and/or C2 are selected according to theselected frequency through L1.

In some embodiments, R3 is in parallel with R2. Optionally, R3 furtheracts as the attenuator (e.g., together with R2) described in the section“Magnetic Switch”.

In some embodiments, D1 is a Zener diode in series between Q1 and Q2.Optionally, D1 defines the current direction.

In some embodiments, R1 is in series with the batteries and ground.Optionally, R1 compensates for the internal resistance of the batteries.

In some embodiments, C1, C3 are capacitors in parallel with thebatteries and the rest of the circuit. Optionally, C1 and C3 help toprevent rebound currents.

Various embodiments and aspects of the present invention as delineatedhereinabove and as claimed in the claims section below find experimentaland/or calculated support in the following examples.

EXAMPLES

Reference is now made to the following examples, which together with theabove descriptions illustrate some embodiments of the invention in a nonlimiting fashion.

Bone Enhancement Experiment

Purpose:

To test the ability of the exemplary enhancement device (e.g., shown inFIG. 7B) to stimulate bone healing and bone density around implants.

Materials:

The bone enhancement device of FIG. 7B comprising an induction coildesigned to fit inside a 5*6 mm (diameter*length) healing cap compatiblewith regular platform internal-hex dental implants. The coil consists ofa 40 um-thick wire making 133 turns in 4 layers around a 0.75*7.5 mm(diameter*length) ferrite core. Optionally, other parameters of the coiland/or core may be used. For example, in some embodiments, the thicknessof the coil may range between 30-80 um, for example 35 um, 50 um, 75 umor intermediate thicknesses. Optionally, in some embodiments, the coilmay be arranged in a different number of layers, for example 3 layers, 6layers, 2 layers or intermediate number of layers. Optionally, in someembodiments, the number of turns of the coil around the ferrite core mayrange between 80-250, for example 90, 140, 189, or intermediate numbers.Optionally, in some embodiments, the dimensions of the ferrite core mayinclude, for example, a diameter ranging between 0.5-1 mm, such as 0.6,0.7, 0.9 mm, or intermediate values, and a length ranging, for example,between 5-10 mm, such as 6 mm, 5.5 mm, 9 mm or intermediate values.

The device was programmed using the exemplary parameters described inthe example in the section “Exemplary Magnetic Field Parameters”. Alsoused was a commercially available dental implant.

Animals:

Twenty four 4-month old male New Zealand White rabbits.

Methods:

6 rabbits were implanted with the device for 2 weeks, and 6 animalsserved as controls. Another 6 rabbits were implanted with the device for4 weeks, and another 6 animals served as controls. The dental implantswere inserted into the proximal metaphysic of one tibia in each of theanimals. The site is easily accessible, composed mainly of trabecularbone, and is a well established model for dental implants. Theenhancement device was threaded on the treatment group, and an emptydevice was threaded on the control group.

At the time of sacrifice, the proximal 20 mm of the tibiae including theimplant were scanned using a 3D x-ray microscopy system XCT400 (Xradia,Calif., USA). Peri-implant bone density was measured on 2D tomographs(close to the middle axis of the implant shank). Trabecular bone volumedensity was measured using NIH ImagJ software. The peri-implant regionwas divided into two subregions, where the region from the healingabutment to half the length of the implant was defined as the “coronary”region, and the distant half as the “apical” region (FIG. 12A, whereA1-A2 are the apical regions and C1-C2 are the coronary regions). In theradial dimension, the region extended from 0.1 mm to 1.1 mm from implantsurface. The cortical bone and the part of the implant shank in contactwith cortical bone were excluded from the analysis. Bone was segmentedout of the surrounding soft tissues and implant using a thresholdingprocedure (FIG. 12B is the segmentation of FIG. 12A). Bone response wasseparately calculated for the coronary and the apical peri-implantregions.

An additional 3D analysis was later performed. The three dimensionalanalysis enabled assessing the newly formed bone volume. Variousparameters such as a percentage of bone to implant contact (BIC orosteointegration percentage OI), the number of trabeculae (Tb.N), thetribecular thickness (Tb.Th), and tribecular spacing (Tb.Sp) weremeasured in a range of 1 mm surrounding the implant.

Results:

Two Dimensional Analysis Results

The vector summation of the magnetic field along the implant axis at 1and 2 mm from implant surface is detailed in FIG. 7C and changes in themagnetic field intensity are graphically presented in FIG. 7A. Themeasured magnetic field intensity was relatively higher in the coronaryarea than the apical area as described in FIGS. 12A-12B. The coronaryregion being at less than 1 mm away radially from the implant surface,and at a distance from the start of the screw (corresponding to bonedepth) of between about 4 to 7 mm.

FIG. 13A graphically represents the results of the 2 week group, andFIG. 13B graphically represents the results of the 4 week group. FIG. 14is a sample of some exemplary CT scans from the 2 week and 4 week activeand control groups, showing higher trabecular bone density aroundimplants in the active group.

The results show that at 2 weeks, there was a 51% increase in thetrabecular bone volume density of the coronary region in the test groupas compared to the control group (p=0.043, FIG. 13A). Bone density inthe apical region increased by 20% in the test group relative to thecontrols.

At 4 weeks, there was no difference in density around the apical areabetween treatment and control groups. However, bone density around thecoronary area of devices in the test group was further stimulated tovalues 78% higher than in the control group (p=0.019, FIG. 13B).

When calculating the entire peri-implant region (apical and coronary),the treatment group experienced an increased peri-implant trabecularbone density of 35% and 43% after 2 and 4 weeks, respectively, ascompared to control (p=0.124 and 0.112, respectively).

In the control group between 2 and 4 weeks post-surgery (bone remodelingphase), peri-implant trabecular bone density decreased from 31.2% to17.7% (i.e. bone density decreased by 43%, p=0.025), due to a decreaseof 53% and 33% in the apical and coronary subregions, respectively(FIGS. 13A-13B). In the test group, bone remodeling was also observed ata very similar extent as bone density decreased by 40% (p=0.048).

Three Dimensional Analysis Results

FIG. 15 graphically represents the results of various parameters thatwere measured at 2 weeks and 4 weeks post implantation. At 2 weeks postimplantation, there was a 56% increase in trabecular bone volume density(BV/TV) of the coronary region in the active group as compared to thecontrol group. Additionally, there was a 44% increase in the number oftrabeculae, and a 48% increase in the BIC (OI) in the active group ascompared to the control group.

At 4 weeks post implantation, there was a 62% increase in trabecularbone volume density (BV/TV) of the coronary region in the active groupas compared to the control group. The BIC(OI) remained steady with a 48%increase in the active group as compared to the control group. A 32%decrease was measured in trabecular spacing (Tb.Sp) in the active groupas compared to the control group, indicating the rise in bone density.The trabecular thickness (Tb.Th) remained almost unaffected. Theincrease in bone volume density in the active group as compared to thecontrol group indicates an approximately 3 times faster bone formationin the active group.

FIGS. 16A-D are some exemplary CT images of the active and controlgroups, showing higher trabecular bone density around implants in theactive group. FIGS. 16A and 16B are images of the control group. FIGS.16C-D are images of the active group. FIGS. 16A and 16C are 2D images(of a single slice), while FIGS. 16B and 16D are 3D images obtained byreconstructing and layering multiple slice images, for example 150 sliceimages. Higher bone density in the bone surrounding the implant can beobserved, for example, on FIG. 16D as opposed to FIG. 16B.

No noticeable signs of infection, inflammation or decay were observed inany of the groups.

CONCLUSION

Results from both two dimensional and three dimensional analysis supportthe hypothesis that the selected magnetic field produced by theenhancement device increases bone density at least at a distance ofabout 2 mm from the surface of the implant and at a bone depth of about4-7 mm. The depth of about 4-7 mm is significant, as this region isparticularly sensitive to bone resorption due to concentration ofmechanical stress during occlusal loading.

Furthermore, results support the hypothesis that the stimulation devicedid not impair bone remodeling.

As was shown in the 3D analysis, all tested parameters such as thenumber of trabeculae, the bone to implant contact, the trabecularspacing and other measured parameters indicate an increasing andaccelerated peri-implant osteogenesis in the active group as compared tothe control group.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated in their entirety by referenceinto the specification, to the same extent as if each individualpublication, patent or patent application was specifically andindividually indicated to be incorporated herein by reference. Inaddition, citation or identification of any reference in thisapplication shall not be construed as an admission that such referenceis available as prior art to the present invention. To the extent thatsection headings are used, they should not be construed as necessarilylimiting.

General

It is expected that during the life of a patent maturing from thisapplication many relevant bone enhancement devices will be developed andthe scope of the term enhancement device is intended to include all suchnew technologies a priori.

As used herein the term “about” refers to ±10%

The terms “comprises”, “comprising”, “includes”, “including”, “having”and their conjugates mean “including but not limited to”.

The term “consisting of” means “including and limited to”.

The term “consisting essentially of” means that the composition, methodor structure may include additional ingredients, steps and/or parts, butonly if the additional ingredients, steps and/or parts do not materiallyalter the basic and novel characteristics of the claimed composition,method or structure.

As used herein, the singular form “a”, “an” and “the” include pluralreferences unless the context clearly dictates otherwise. For example,the term “a compound” or “at least one compound” may include a pluralityof compounds, including mixtures thereof.

Throughout this application, various embodiments of this invention maybe presented in a range format. It should be understood that thedescription in range format is merely for convenience and brevity andshould not be construed as an inflexible limitation on the scope of theinvention. Accordingly, the description of a range should be consideredto have specifically disclosed all the possible subranges as well asindividual numerical values within that range. For example, descriptionof a range such as from 1 to 6 should be considered to have specificallydisclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numberswithin that range, for example, 1, 2, 3, 4, 5, and 6. This appliesregardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to includeany cited numeral (fractional or integral) within the indicated range.The phrases “ranging/ranges between” a first indicate number and asecond indicate number and “ranging/ranges from” a first indicate number“to” a second indicate number are used herein interchangeably and aremeant to include the first and second indicated numbers and all thefractional and integral numerals therebetween.

As used herein the term “method” refers to manners, means, techniquesand procedures for accomplishing a given task including, but not limitedto, those manners, means, techniques and procedures either known to, orreadily developed from known manners, means, techniques and proceduresby practitioners of the chemical, pharmacological, biological,biochemical and medical arts.

As used herein, the term “treating” includes abrogating, substantiallyinhibiting, slowing or reversing the progression of a condition,substantially ameliorating clinical or aesthetical symptoms of acondition or substantially preventing the appearance of clinical oraesthetical symptoms of a condition.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

What is claimed is:
 1. A system for bone enhancement comprising: a device adapted for insertion into a bone implant, said device including a housing including an implantable portion sized and shaped for implantation into the bone, a first transmitter at least partially inserted into said implantable portion of said housing, said first transmitter arranged to transmit at least a bone enhancing magnetic field for said bone enhancement and a magnetic switch coupled to activate said first transmitter to an active state that continues for a treatment period, said magnetic switch activated by an external magnetic field and said first transmitter remaining in said active state after removal from said external magnetic field; and a cradle having a recess sized and shaped to fit said device, said cradle including second transmitter arranged to produce said external magnetic field.
 2. The system of claim 1, wherein said first transmitter is configured for magnetic pulses at a repetition rate of 0.5 Hz to 50 Hz.
 3. A system as in claim 1, wherein said first transmitter comprises at least one wire coil wound and stacked around a core and at least partially inserted into said implantable portion of said housing, said wire coil configured to produce said bone enhancing magnetic field.
 4. The system of claim 3, wherein said first transmitter is configured for applying a current having a peak amplitude from 50 mA to 150 mA to said wire coil to produce said bone enhancing magnetic field.
 5. A system as in claim 3, further comprising: a controller disposed in said device controlling said first transmitter, and a receiver connected to said wire coil for receiving an external magnetic field coded for programming said controller.
 6. The system of claim 3, wherein a number of windings of said wire coil, a diameter of a wire of said wire coil and a number of wires stacked around said core are selected to reduce heating while transmitting said bone enhancing magnetic field.
 7. A system as in claim 6, wherein said device is sized and arranged for insertion in a jaw bone implant for an artificial tooth, said device extending to an end of a cavity of said implant.
 8. A system as in claim 6, wherein a diameter of said at least one wire ranges from about 10 μm to about 80 μm, a diameter of a winding of said wire coil around said core is about 800 μm to about 1150 μm, and a number of windings of said wire around said core ranges from about 450 to about
 550. 9. A system as in claim 6, wherein said heating of said bone and said bone enhancing magnetic field are selected to synergistically increase osteointegration in said bone, wherein said bone is heated by about 0.02 degrees Celsius to about 3 degrees Celsius during steady state.
 10. A system according to claim 6, wherein said device comprises an energy saving circuit, said circuit comprising: a capacitor in series with said wire coil, said capacitor being able to store sufficient charge to pass a current through said coil to produce said bone enhancing magnetic field; one or more switches in series with said capacitor; and a controller to: control said switches to maintain said capacitor at a first voltage value during a non-pulse phase, wherein no significant magnetic field is produced, control said switches to charge said capacitor to a second voltage value, said second voltage value equal to about said first voltage value, said second voltage value having a charge opposite to said first voltage value; and control said switches to charge said capacitor from said second voltage value back to said first voltage value, said charging occurring over a time period of a pulse phase, wherein said charging said capacitor comprises passing a current through said coil to produce said bone enhancing magnetic field, said current related to a voltage drop across said coil of about two times said first voltage.
 11. A system as in claim 10, wherein a voltage source of about 3 Volt is used, wherein at least one of said first voltage value and said second voltage value is charged within about 25 microseconds, and wherein a peak current is reached during a single voltage swing.
 12. A system as in claim 1, further comprising: an attenuator arranged to prevent self reset of said first transmitter.
 13. A system as in claim 1, wherein said external magnetic field is arranged for wirelessly charging batteries in said device.
 14. The system of claim 1, wherein said first transmitter is configured for applying said bone enhancing magnetic field having a magnetic flux density of about 0.05-0.5 mT at up to at least about 2 mm from a surface of said implant.
 15. A system for bone enhancement comprising a device adapted for insertion into a bone implant, said device comprising: a housing including an implantable portion sized and shaped for implantation into the bone a first transmitter at least partially inserted into said implantable portion of said housing, said first transmitter arranged to transmit at least a bone enhancing magnetic field for said bone enhancement; a magnetic switch coupled to activate said first transmitter to an active state that continues for a treatment period, said magnetic switch activated by an external magnetic field and said first transmitter remaining in said active state after removal from said external magnetic field and a second transmitter arranged to produce said external magnetic field; said second transmitter including a cradle shaped and sized to stand stably on a flat structure and for mechanically engaging said device to support said device while activating the device with said external magnetic field outside of said bone implant.
 16. The system of claim 15, wherein said first transmitter is configured to produce around said implant said bone enhancing magnetic field having a magnetic flux density of about 0.05-0.5 mT at up to at least about 2 mm from a surface of said implant.
 17. A system as in claim 15, wherein said cradle is shaped and sized to support said device while the device is inside a sterile package.
 18. A system as in claim 15, wherein said cradle comprises at least one of an input for allowing remote activation of said device by a user, and an output for allowing a user to determine a state of said device.
 19. The system as in claim 15, wherein said device is sized and arranged for insertion in a jaw bone implant for an artificial tooth, said device extending to an end of a cavity of said implant.
 20. The system of claim 15, wherein said first transmitter is configured for magnetic pulses at a repetition rate of 0.5 Hz to 50 Hz.
 21. A system for bone enhancement comprising: a device adapted for insertion into a bone implant, said device including a housing including an implantable portion sized and shaped for implantation into the bone, a first transmitter at least partially inserted into said implantable portion of said housing, said first transmitter arranged to transmit at least a bone enhancing magnetic field for said bone enhancement and a magnetic switch coupled to activate said first transmitter to an active state that continues for a treatment period, said magnetic switch activated by an external magnetic field and said first transmitter remaining in said active state after removal from said external magnetic field; a second transmitter arranged to produce said external magnetic field; and a testing circuit including a coil for testing the power level generated by said implantable device by measuring a current induced by the bone enhancing magnetic field on the coil.
 22. The system of claim 21, wherein said first transmitter is configured to produce around said bone implant said bone enhancing magnetic field having a magnetic flux density is at least one of: about 0.2-0.45 mT at up to at least about 1 mm from a surface of said implant, and about 0.2-0.3 mT up to at least about 2 mm from said surface.
 23. The system of claim 21, wherein said said first transmitter is configured to produce said bone enhancing magnetic field having a pulse duration that ranges from about 30 to 70 microseconds followed by a wait time that is 1500-2400 times as long as said pulse duration.
 24. The system of claim 21, wherein said said first transmitter is configured to produce a a biphasic, sinusoidal pulse of current to produce said magnetic field.
 25. The system of claim 21, wherein said first transmitter is configured for magnetic pulses at a repetition rate of 0.5 Hz to 50 Hz.
 26. A system as in claim 21, further comprising: an attenuator arranged to prevent self reset of said first transmitter. 